376 PEOF. E. E. LANKESTEE ON CEETAIN POINTS IN THE 



The system is an absolute failure. The number ai\d size of the lateral eyes is not 

 even constant in the same individual (the two sides differing sometimes) ; much less is 

 it so in species and still less in genera. The only generalization which can be made 

 about the lateral eyes, is that in the Scorpions with triangular sternum, they are 

 usually more numerous than in those with pentagonal sternum ; but not even in 

 reference to such large sections can a strictly accurate statement of the kind be made. 



Peters made a great advance in recognizing the form of the sternum (or metasternite, 

 the equivalent of the chilaria of Limulus) as a basis for a primary division of the 

 Scorpions. He combined with the consideration of this character a reference to the 

 dentition of the chelicera? ; and thus was led to establish four groups or subfamilies of 

 the family Scorpionidse (the Linnean genus Scorpio), viz. : — 



Group I. Telegonini. 



Sternum linear ; two or three lateral eyes ; both the fixed and the movable joint of 

 the chelicera have a single row of teeth. 



Genera: — Tel 'e g onus, Koch ; Cercophonius, Peters ; Acanthochirus, Peters ; Bothri- 

 urus, Peters. 



Group II. Scorpionini. 



Sternum quadrate or pentagonal ; both the fixed and the movable joint of the cheli- 

 cera have a single row of teeth. 



Genera: — Vejovis, Koch ; Brotheas, Koch ; Scorpio, Linne in part ( = Scorpius, Ehr.) ; 

 Scorpiops, Peters ; Uroda cus, Peters ; Hemiscorpion, Peters ; Ischnnrus (Sisyphus, Koch), 

 Gervais; Opisthacanthus, Peters ; Bacurus, Peters ; Opisthophthalmus (Atreus), Koch ; 

 Ueterometrus, Ehr. (=Buthus in part, Ehr., not Leach) ; Biplocentrus, Peters. 



Group III. Centrukini. 



Sternum triangular ; movable ramus of chelicera with two rows of teeth, the fixed 

 ramus with one row. Hands of the chelae spindle-shaped. Often a spine beneath the 

 sting. 



Genera: — Centrums, Ehr. (not Koch, =Tithyus of Koch, Atreus of Gervais, not 

 Koch) ; TJroplectes, Peters. 



Group IV. Andkoctoxini. 



Sternum triangular ; both rami of the chelicera with two rows of teeth. No spine 

 beneath the sting. 



Genera : — Prionnrus, Ehr. ; Buthus, Leach. 



